Because of ever greater miniaturization of semiconductor components, such components will increasingly be built in stacked form in the future. Accordingly, a need exists for an optimized method for production of such stacked semiconductor products. A method to stack semiconductor components vertically consists in, i.a., outfitting a wafer on both sides with semiconductor elements, in particular dices and/or chips on both sides. On both sides of the wafer, there is therefore a large number of semiconductor components, which are connected via contact points in further process steps to corresponding wafers that are outfitted in each case on both sides with semiconductor components. Because of the ever smaller components, in particular dices and/or chips, it is of decisive importance that the corresponding contact points of the semiconductor components align with one another as precisely as possible, thus are oriented vertically to one another. In the case of an inaccurate orientation or movement of the semiconductor components, in particular the contact points of the semiconductor components on the opposite sides of the wafer, the corresponding contacts would not—or not adequately—be connected to one another. For this reason, a check of the position of the contact points on the top and bottom of each wafer takes place.
Since a large number of contact points on each wafer are to be examined, and in particular, the orientation of each contact point with the respective opposite contact point is relevant, this check is time-consuming and accordingly costly.
To determine the orientation errors of opposite contact points, it has proven to be effective to detect the position of each contact point on each substrate side in a first rotational position of the substrate and in a second rotational position that is rotated by 180 degrees relative to the first rotational position. The rotation by 180 degrees (that is performed in this case) has the effect that measuring inaccuracies introduced by the optical positional detection means are almost canceled out, and filtered from the measuring result. In this respect, a technical problem exists. After rotation of the substrate, first the new position with the lens to be used as a detection means has to be approached approximately (so-called pre-alignment).